Communication method, base station and user equipment using a set of legacy or aggressive CQI table and legacy or aggressive MCS table

ABSTRACT

The present disclosure provides a communication method, base station and user equipment for configuring a parameter table in a wireless communication system including a base station and a user equipment, the communication method comprising: defining at both the base station and the user equipment a parameter table which includes whole entries of a legacy parameter table and extended entries; and transmitting from the base station to the user equipment a bitmap indication which indicates a sub-table selected from the parameter table, wherein the number of the entries in the sub-table is the same as in the legacy parameter table.

BACKGROUND Technical Field

The present disclosure relates to parameter table configurationtechnique in the communication field.

Description of the Related Art

In 3GPP (3rd Generation Partnership Project) Rel. 8/9/10 system, ChannelQuality Indicator (CQI), one type of channel state information (CSI), isan important communication parameter used for scheduling and linkadaptation at eNodeB (eNB). In practice, since UE (user equipment) knowsbetter about the downlink channel based on certain reference signal,like CRS (common reference signal) or CSI-RS (channel stateinformation-reference signal), CQI is calculated and recommended at UEside. Then, CQI is feedback by the UE with a certain index in the CQItable, which includes some combinations of modulation order and codingrate, referring to Table 7.2.3-1 in 3GPP TS 36.213 V10.5.0, which isentirely incorporated hereto by reference.

FIG. 1 shows the CQI table in TS 36.213. It can be seen from FIG. 1 thatthe standard CQI table, which may also be referred to as a legacy CQItable, includes 16 entries with indices from 0-15, corresponding tomodulation schemes such as QPSK, 16QAM and 64QAM. Therefore, 4 bits arenecessary to reflect a certain entry when the UE feedbacks a certainwideband CQI to the eNB.

As to other CQI types defined according to different feedback modes ortransmission modes, such as subband CQI, spatial CQI or UE selected CQI,UE do not directly feedback the entry/index in the same CQI table asshown in FIG. 1. Instead, an implicit mechanism is used to feedbacktheir CQI offset level from the wideband CQI value. For example,Subband differential CQI offset level=subband CQI index−wideband CQIindex.

FIG. 2 shows the subband differential CQI table in TS 36.213. It can beseen that the standard subband differential CQI table, which may also bereferred to as a legacy subband differential CQI table, includes 4entries with indices from 0 to 3. Therefore, UE needs 2 additional bitsto feedback the subband differential CQI offset level.

Also, Modulation Coding Scheme (MCS) is an important communicationparameter in 3GPP Rel. 8/9/10 system. MCS refers to which combination ofmodulation order and coding rate is used in physical transmission ofdownlink and uplink. There is also a table, called MCS table, restrictswhich combination of modulation order and transport block size could beused.

FIG. 3 shows the MCS table in TS 36.213. It can be seen that thestandard MCS table, which may also be referred to as a legacy MCS table,includes 32 entries with indices from 0-31, corresponding to modulationorders such as 2, 4 and 6. The last three entries with indices 29-31 areused for re-transmission. In 3GPP, which MCS is used is informed inDownlink Control Information (DCI). And 5 bits are necessary for thisindication.

BRIEF SUMMARY

With the future introduction of new technologies and new networkdeployment, such as 3D beamforming, massive MIMO and dense deployment ofsmall cell, etc., user equipment has more opportunities to maintain highquality wireless channel link with high SINR, so it is possible andbeneficial for the system to support higher modulation orders thancurrent system, like 256QAM or 1024QAM, in order to further improve thespectral efficiency and user throughput.

Correspondingly, there is a need to configure the parameter table, suchas the CQI table or the MCS table described above, so that more entriescorresponding to higher modulation orders and/or coding rates than thosein the legacy tables can be indicated. There is also a need to configurethe differential CQI table to indicate more CQI offset levels, so thatthe indication of the differential CQI can be more accurate.

The present disclosure is made in consideration of the above aspects.

According to one aspect of the present disclosure, there is provided acommunication method of configuring a parameter table in a wirelesscommunication system including a base station and a user equipment,comprising: defining at both the base station and the user equipment aparameter table which includes whole entries of a legacy parameter tableand extended entries; and transmitting from the base station to the userequipment a bitmap indication which indicates a sub-table selected fromthe parameter table.

According to another aspect of the present disclosure, there is provideda communication method of configuring a parameter table in a wirelesscommunication system including a base station and a user equipment,comprising: defining at both the base station and the user equipmentmultiple parameter tables which include at least a legacy parametertable and an aggressive parameter table which includes new modulationorder related entries or new combinations of modulation order and codingrate; and transmitting from the base station to the user equipment anindication which indicates a parameter table selected from the multipleparameter tables, wherein the number of entries in any one of themultiple parameter tables is the same as in the legacy parameter tableto keep signaling overhead unchanged.

According to a further aspect of the present disclosure, there isprovided a communication method of configuring a parameter table in awireless communication system including a base station and a userequipment, comprising: defining at both the base station and the userequipment a parameter table which includes whole entries of a legacyparameter table and extended entries; and transmitting from the basestation to the user equipment an indication which indicates one entry ofthe parameter table, by legacy bits and at least one unused bit jointly.

According to a further aspect of the present disclosure, there isprovided a communication method of configuring a parameter table in awireless communication system including a base station and a userequipment, comprising: defining at both the base station and the userequipment a parameter table which includes whole entries of a legacyparameter table and extended entries; and transmitting from the basestation to the user equipment an indication which indicates one entry ofthe parameter table by a number of bits, wherein the number of bitscorresponds to the number of entries in the parameter table.

According to a further aspect of the present disclosure, there isprovided a base station for configuring a parameter table in a wirelesscommunication system including the base station and a user equipment,comprising: a storing unit which stores a pre-defined parameter tableincluding whole entries of a legacy parameter table and extendedentries; and a transmitting unit which transmits to the user equipment abitmap indication which indicates a sub-table selected from thepre-defined parameter table, wherein the number of the entries in thesubtable is the same as in the legacy parameter table.

According to a further aspect of the present disclosure, there isprovided a user equipment for configuring a parameter table in awireless communication system including a base station and the userequipment, comprising: a storing unit which stores a pre-definedparameter table including whole entries of a legacy parameter table andextended entries; and a receiving unit which receives from the basestation a bitmap indication which indicates a sub-table selected fromthe pre-defined parameter table, wherein the number of the entries inthe subtable is the same as in the legacy parameter table.

According to a further aspect of the present disclosure, there isprovided a communication method of configuring different CQI tables fordifferent CQI types considering wideband CQI is explicitly indicated byCQI table but other CQI type like spatial CQI, subband CQI orUE-selected CQI is implicitly indicated by subband differential CQItable.

According to a further aspect of the present disclosure, there isprovided a communication method of configuring new parameter table in awireless communication system including a base station and the userequipment, in which there is no half closed-interval definition foroffset levels. Instead, only values have been defined in the table andthe indicated values based on bitmap form the full closed-interval tableautomatically.

According to the communication methods and communication apparatuses ofvarious aspects of the present disclosure, more entries than those inthe legacy tables can be indicated. Thereby, higher modulation orderscan be supported to adapt channel and improve spectral efficiency butwithout increasing the reported overhead.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

These and/or other aspects and advantages of the present disclosure willbecome more distinct and easier to be understood in a detaileddescription of embodiments of the present disclosure below incombination with attached drawings, in which:

FIG. 1 is a diagram showing the legacy CQI table in the conventionalcommunication system;

FIG. 2 is a diagram showing the legacy subband differential CQI table inthe conventional communication system;

FIG. 3 is a diagram showing the legacy MCS table in the conventionalcommunication system;

FIG. 4 is a diagram schematically showing communication scenarios whereUE has different modulation/coding rate requirements at differentpositions;

FIG. 5 is a diagram schematically showing communication scenarios wheredifferent carrier components (CCs) have different modulation/coding raterequirements;

FIG. 6 is a diagram schematically showing communication scenarios wheredifferent links have different modulation/coding rate requirements;

FIG. 7 is a flowchart showing an exemplary implementation of acommunication method according to a first embodiment of the presentdisclosure;

FIG. 8 is a diagram schematically showing an extended CQI table andcorresponding bitmap examples according to the first embodiment of thepresent disclosure;

FIGS. 9a and 9b are diagrams schematically showing two kinds of extendeddifferential CQI tables and corresponding bitmap examples according tothe first embodiment of the present disclosure;

FIGS. 10a and 10b are diagrams schematically showing two kinds ofextended MCS tables based on positions of reserved entries andcorresponding bitmap examples according to the first embodiment of thepresent disclosure;

FIG. 11 is a diagram schematically showing the configuration of a basestation according to the first embodiment of the present disclosure;

FIG. 12 is a diagram schematically showing the configuration of a userequipment according to the first embodiment of the present disclosure;

FIG. 13 is a flowchart showing an exemplary implementation of acommunication method according to a second embodiment of the presentdisclosure;

FIG. 14 is a diagram schematically showing a legacy parameter table andan aggressive parameter table according to the second embodiment of thepresent disclosure;

FIG. 15 is a diagram schematically showing the configuration of a basestation according to the second embodiment of the present disclosure;

FIG. 16 is a diagram schematically showing the configuration of a userequipment according to the second embodiment of the present disclosure;

FIG. 17 is a flowchart showing an exemplary implementation of acommunication method according to a third embodiment of the presentdisclosure;

FIG. 18 is a flowchart showing an exemplary implementation of acommunication method according to a fourth embodiment of the presentdisclosure; and

FIG. 19 is a diagram schematically showing a new transmission formataccording to the fourth embodiment of the present disclosure.

DETAILED DESCRIPTION

In the following detailed description, reference is made to theaccompanying drawings, which form a part thereof. In the drawings,similar symbols typically identify similar components, unless contextdictates otherwise. It will be readily understood that the aspects ofthe present disclosure can be arranged, substituted, combined, anddesigned in a wide variety of different configurations, all of which areexplicitly contemplated and make part of this disclosure.

First Embodiment

A communication method of configuring a parameter table in a wirelesscommunication system including an eNode B and a UE is provided in thefirst embodiment of the present disclosure. The communication methodcomprises the steps of: defining at both the eNode B and the UE aparameter table which includes whole entries of a legacy parameter tableand extended entries; and transmitting from the eNode B to the UE abitmap indication which indicates a sub-table selected from theparameter table, wherein the number of the entries in the sub-table isthe same as in the legacy parameter table.

Before the detailed explanation on the implementation of thecommunication method according to the first embodiment of the presentdisclosure, a description will be made to different communicationscenarios of UE as well as different requirements on modulationorder/coding rate, with reference to FIGS. 4-6.

FIG. 4 is a diagram schematically showing communication scenarios whereUE has different modulation/coding rate requirements at differentpositions.

As shown in FIG. 4, UE 401 is in a local area or massivemultiple-input-multiple-output (MIMO) scenario 400. It is found that UE401 may have different requirements on modulation order/coding rate atdifferent positions. For example, UE 401 will experience differentsignal-to-noise ratio (SINR) conditions when it is at differentpositions. Specially, if UE 401 is moving slowly from cell edge (e.g.,position A) to a position (e.g., position B) closer to the cell center,and finally to the cell center (e.g., position C), it will experiencelow SINR, medium-high SINR and very high SINR conditions, respectively.Obviously, low SINR area needs a relatively lower effective coding rate,while high SINR area needs a relatively high effective coding rate.

FIG. 5 is a diagram schematically showing communication scenarios wheredifferent carrier components (CCs) have different modulation/coding raterequirement.

In the scenario of carrier aggregation (CA), as shown in FIG. 5,similarly, it is found that different CCs may also have differentmodulation/coding rate requirements due to differentSINR/interference/channel conditions. For example, for CCs from Pcell toUE, such as carrier 1, there may be a requirement on a conservative CQItable (e.g., the legacy CQI table) for robust access; while for CCs fromScell to UE, such as carrier 2, there may be a requirement on anaggressive CQI table for boosting throughput.

FIG. 6 is a diagram schematically showing communication scenarios wheredifferent links have different modulation/coding rate requirement.

In the scenario of FIG. 6, similarly, it is found that uplink anddownlink may have different modulation/coding rate requirements due todifferent SINR/interference/channel conditions. For example, fordownlink transmissions, there may be a requirement on a conservative CQItable (e.g., the legacy CQI table) due to much active downlink traffic;while for uplink transmissions, there may be a requirement on anaggressive CQI table due to less uplink traffic, and hence high SINR.

From FIGS. 4-6, it is expected that different parameter tables, such asCQI/MCS table, which include special combinations of modulationorder/coding rate, could be used in different SINR conditions to adaptdifferent channel and get better performance. In other words, there isno need to apply the same parameter table for different communicationscenarios. Only some entries in the parameter table may be enough in acertain communication scenario.

The communication method according to the first embodiment of thepresent disclosure is designed in view of the above analysis, in orderto meet different modulation/coding rate requirements.

Now, a detailed description on the communication method according to thefirst embodiment of the present disclosure will be made with referenceto FIG. 7.

FIG. 7 is a flowchart showing an exemplary implementation of thecommunication method according to the first embodiment of the presentdisclosure. The communication method according to the first embodimentis used for configuring a parameter table in a wireless communicationsystem including an eNode B and a UE.

As shown in FIG. 7, the communication method starts at step 701, where aparameter table is defined at both the eNode B and the UE.

The parameter may be various communication parameters communicatedbetween UE and eNode B. For example, the parameter may be CQI,differential CQI offset level and/or MCS. Correspondingly, the parametertable may be a CQI table, a differential CQI table or a MCS table.

In addition, the parameter table may include the whole entries of alegacy parameter table and some extended entries. The entries of thelegacy parameter table may be standard entries defined in standards suchas 3GPP TS 36.213, and they may correspond to communication scenarioswhere relatively conservative modulation orders/coding rates arerequired. The extended entries may be extended entries defined accordingto the first embodiment of the present disclosure, and they maycorrespond to communication scenarios where relatively aggressivemodulation orders/coding rates are required.

Next, at step 702, the eNode B transmits to the UE a bitmap indicationwhich indicates a sub-table selected from the parameter table.

Specially, the bitmap indication may be transmitted by the eNode B tothe UE via a signaling in the upper layer or in the physical layer. Forexample, the bitmap indication may be transmitted via the Radio ResourceControl (RRC) signaling semi-statically or implicitly triggered via bitsin Downlink Control Information (DCI) format dynamically(specificconfigurations are via RRC signaling).

The bitmap may be used for indicating the sub-table selected from theparameter table. It should be noted that the number of the entries inthe sub-table is the same as in the legacy parameter table, so that thesignaling overhead related to the indication in the physical layer iskept unchanged.

The bitmap may be generated by the eNode B based on the communicationscenarios of the wireless communication system as described abovetypically or any other suitable scenarios.

After the eNode B transmits to the UE the bitmap indication, both theeNode B and the UE are aware of the sub-table currently in use, so theymay communicate an index of an entry in the parameter sub-table witheach other. For example, for the CQI table, UE may report the CQI indexto the eNode B based on the sub-table and eNB clearly know the exactlysame table where UE is referring to. For the MCS table, the eNode B mayinform the UE of the MCS index and UE assumes the same MCS table as thatin eNB.

Moreover, since the extended parameter table comprises more entries thanthe legacy table, the method of the first embodiment of the presentdisclosure may further comprise a re-indexing process and a restoringprocess, which will be described later, to keep the feedback bitsunchanged.

Next, a few examples will be given with reference to FIGS. 8-10 tobetter explain the principle of bitmap.

First, a description will be made to a case where the bitmap is appliedto the CQI table. FIG. 8 is a diagram schematically showing an extendedCQI table and corresponding bitmap examples according to the firstembodiment of the present disclosure. The CQI table as shown in FIG. 8,which may also be referred to as the extended CQI table, includes 27entries with indices from 0-26. Each entry corresponds to a certain CQIvalue with a corresponding modulation order and coding rate. It shouldbe noted that the values of the entries and the number of the entries inthe extended CQI table are only examples, and are not limited thereto.

Comparing with the legacy CQI table as shown in FIG. 1, it can be seenthat the extended CQI table includes the whole entries with indices from0-15 of the legacy CQI table, and new extended entries with indices from16-26. Thus the number of the entries in the extended CQI table is morethan that in the legacy CQI table.

According to the analysis as described above, for differentcommunication scenarios, there is no need to apply the whole extendedCQI table, and only some entries in the extended CQI table may be enoughin a certain communication scenario.

For example, for UE at the edge of the cell (e.g., position A as shownin FIG. 4), it experiences a low SINR condition, and requires a CQItable with relatively conservative CQI values, i.e., relatively lowereffective coding rates and/or relatively lower modulation orders. Themethod according to the first embodiment of the present disclosure mayconfigure a sub-table (a conservative CQI table in this case) selectedfrom the extended CQI table, with a bitmap as shown in column 801 ofFIG. 8. Exemplarily, the value of “1” in the corresponding position ofthe bitmap may indicate, for example, the existence of the correspondingentry in the sub-table; while the value of “0” in the correspondingposition of the bitmap may indicate, for example, the absence of thecorresponding entry in the sub-table; or vice versa. It can be seen fromthe bitmap 801 that entries with lower effective coding rates andmodulation orders (e.g., QPSK, 16QAM and 64QAM) are configured in thiscase.

For UE at a position closer to the middle of the cell than the edge(e.g., position B as shown in FIG. 4), it experiences a medium SINRcondition, and requires a CQI table with relatively medium CQI values.The method according to the first embodiment of the present disclosuremay configure a sub-table (a medium CQI table in this case) selectedfrom the extended CQI table, with a bitmap as shown in column 802 ofFIG. 8. It can be seen from the bitmap 802 that entries with mediumeffective coding rates and modulation orders are configured in thiscase.

Similarly, for UE at the center of the cell (e.g., position C as shownin FIG. 4), it experiences a high SINR condition, and requires a CQItable with relatively aggressive CQI values, i.e., relatively highereffective coding rates and/or relatively higher modulation orders. Themethod according to the first embodiment of the present disclosure mayconfigure a sub-table (an aggressive CQI table in this case) selectedfrom the extended CQI table, with a bitmap as shown in column 803 ofFIG. 8. It can be seen from the bitmap 803 that more entries with highereffective coding rates and modulation orders, for example, 256QAM, areconfigured in this case. Also, a few entries with lower effective codingrates and modulation orders (e.g., QPSK) are configured to accommodateoccasional cases.

It should be noted that the three bitmaps 801-803 are only examples, andthose skilled in the art can configure the CQI table with differentbitmaps according to the communication scenario.

It should also be noted that, for the extended CQI table, UE shouldre-order (re-index) the entries in the sub-table so that the indexlength is still the same as legacy CQI table. At eNB, it may restore thereceived index to the original index according to the bitmap.

For example, in FIG. 8, UE chooses CQI index 20 based on restriction ofbitmap 2. Then, UE may re-index the original entries in the sub-tableindicated by the bitmap 2, and the original index 20 will be changed toa new index 15 which will be feedback to eNB. eNB will restore the index15 into the original index 20 based on the bitmap 2. So there is noambiguity between eNB and UE. eNB always knows what kind of table UE isusing currently based on the bitmap based configuration.

Therefore, it can be seen from FIG. 8 that more coding rates andmodulation orders, for example, 256QAM or higher, are supported by thebitmap, and there is a flexibility to select certain coding rates andmodulation orders in order to adapt different communication scenarios,thus achieving the best performance. But at the same time, therestriction is only used for wideband CQI. For other CQI types likespatial CQI or subband CQI, there is no need to restrict that. UE couldutilize differential CQI offset level to feedback any entry or index inextended CQI table for spatial CQI or subband CQI. The details andexamples would be introduced later.

Moreover, as described above, the bitmap indication may be transmittedby the eNode B to the UE via an upper layer signaling, such as the RRCsignaling, which keeps the signaling overhead in the physical layerunchanged.

In addition, the number of entries in the CQI sub-table is 16, which isthe same as that in the legacy CQI table, so that a good backwardcompatibility and overhead is ensured and only a small modification tothe standard is needed.

Next, a description will be made to a case where the bitmap is appliedto the differential CQI table. FIGS. 9a and 9b are diagramsschematically showing two kinds of extended differential CQI tables andcorresponding bitmap examples according to the first embodiment of thepresent disclosure.

First, referring to FIG. 9a , the extended differential CQI table 901includes the whole entries with indices from 0-3 of the legacydifferential CQI table as shown in FIG. 2, and new extended entries withindices from 4-7. Similarly, the values of the entries and the number ofthe entries in the extended differential CQI table are only examples,and those skilled in the art may design an extended differential CQItable comprising more or less number of entries with different values.The option shown in FIG. 9a is direct extension and still keeps thelegacy entries/values.

As shown in FIG. 9a , for relatively small offset levels, such as 2 dB,the method according to the first embodiment may configure a sub-tableselected from the extended differential CQI table, with the bitmap 1 asshown in column 902 of FIG. 9a , which indicates the same entries asthose in the legacy differential CQI table. For relatively large offsetlevels, such as 5 or 6 dB, the method according to the first embodimentmay configure a sub-table selected from the extended differential CQItable, with the bitmap 2 as shown in column 903 of FIG. 9a , whichindicates extended entries corresponding to large offset levels.

Option in FIG. 9a achieves a good backward compatibility. On the otherhand, FIG. 9b is a differential CQI table completely redefined accordingto the first embodiment of the present disclosure, which includesentries totally different from those in the legacy differential CQItable. In FIG. 9b , no half-closed intervals as in the legacydifferential CQI table have been defined. Instead, only some values havebeen defined. After indication of selected entries via bitmap, thosevalues form closed-set automatically. For example, the method accordingto the first embodiment may configure a sub-table as shown in sub-table908, with the bitmap 1 as shown in column 905. The method according tothe first embodiment may also configure a sub-table as shown insub-table 907, with the bitmap 2 as shown in column 906. The advantageof the extended differential CQI table like FIG. 9b is that it may beeasier to further extend the differential CQI table to include moreentries. In other words, it achieves a good forward compatibility, sinceonly some new values instead of half-closed intervals are needed to bedefined.

It should be noted that wideband CQI and subband/spatial/UE selected CQIdo not need to use the same CQI table in the above descriptions. Thatis, the selection of a wideband CQI entry may be restricted to the CQIsub-table to keep overhead unchanged, but the selection of asubband/spatial/UE selected CQI entry may not be restricted to the CQIsub-table and may be based on the whole extended CQI table. That isbecause the subband/spatial/UE selected CQI is indirectly reflected by adifferential CQI offset level, instead of directly reflected by a realCQI value as described above.

In other words, when a subband differential CQI is to be reported as theparameter, the index of a subband differential CQI entry can bedetermined based on a CQI sub-table selected from an extended CQI tableby the bitmap. Alternatively, the index of the subband differential CQIentry can be determined based on the whole extended CQI table.

For example, a wideband CQI may be restricted by bitmap 2 as shown inFIG. 8, and UE feedbacks a CQI index 16. But a subband CQI may not berestricted by the bitmap 2 and any entry in the whole extended CQI tablecould be used, even when it is not indicated by the bitmap 2, such asCQI index 22. So in this case UE only needs to feedback a CQI offsetlevel 6 (22−16=6) based on the subband differential CQI table as shownin FIG. 9a or 9 b.

That is, when a wideband CQI is to be reported as the parameter, thewideband CQI is determined based on a CQI sub-table selected from theextended CQI table by bitmap. When a spatial CQI, a subband CQI or aUE-selected CQI is to be reported as the parameter, the spatial CQI, thesubband CQI or the UE-selected CQI is to be determined based on thefollowing: (1) Wideband CQI, which is based on the extended CQI table,or the CQI sub-table selected from the extended CQI table; and (2) adifferential CQI offset level based on sub-table, which is selected fromthe extended differential CQI offset level table by bitmap.

It should also be noted that a re-indexing and restoring process may beapplied for the extended CQI table as described above. But for thedifferential CQI table, the re-indexing and restoring process may not benecessary. For example, if UE chooses CQI index 20 for wideband CQI andindex 22 for subband CQI, then only the index 2 (based on differentialCQI table) should be feedback.

With the extended differential CQI table according to the firstembodiment of the disclosure, the feedback accuracy of differential CQImay be improved without an increase of signaling overhead.

Next, a description will be made to a case where the bitmap is appliedto the MCS table. FIGS. 10a and 10b are diagrams schematically showingtwo kinds of extended MCS tables and corresponding bitmap examplesaccording to the first embodiment of the present disclosure. Theextended MCS table as shown in FIGS. 10a and 10b , includes 42 entrieswith indices from 0-41. Similarly, the values of the entries and thenumber of the entries in the extended MCS table are only examples, andare not limited thereto.

FIG. 10a and FIG. 10b show two different patterns based on differentpositions of reserved table for retransmission. eNB and UE should assumethe same bitmap or selected table after the indication in order to avoidambiguity. Furthermore, considering some initial state or handover statethat UE will not know the configuration of MCS tables, legacy tables maybe used in that cases. In those scenarios eNB generally uses DCI format1A for downlink transmission. So the legacy MCS table may be used asdefault setting in DCI format 1A transmission. The extended MCS tablemay only be used for DCI format 2C or future formats.

Similarly, the bitmaps in FIGS. 10a and 10b are only examples, and thoseskilled in the art can configure the MCS table with different bitmapsaccording to the communication scenario.

The communication method according to the first embodiment of thepresent disclosure has been described above. According to thecommunication method, more entries corresponding to more modulationorders/coding rates than those in the legacy tables may be indicated bythe bitmap. Thereby, higher modulation orders may be supported to adaptchannel and improve spectral efficiency, and certain coding rates andmodulation orders may be selected flexibly according to differentcommunication scenarios, thus achieving the best performance.

Moreover, since the bitmap indication may be transmitted by eNode B toUE via an upper layer signaling, such as the RRC signaling, thesignaling overhead in the physical layer may be kept unchanged.

In addition, the number of entries in the sub-table may be the same asthat in the legacy parameter table, so that a good backwardcompatibility may be ensured and only a small modification to thestandard is needed.

Hereinafter, the communication apparatus according to the firstembodiment of the present disclosure will be described with reference toFIGS. 11-12. The communication apparatus may be a base station (whichmay also be referred to as eNode B or eNB) or a user equipment (UE), andlocates in a wireless communication system comprising both the basestation and the UE.

First, refer to FIG. 11, which schematically shows the configuration ofa base station according to the first embodiment of the presentdisclosure. The base station 1100 according to the first embodiment isused to configure a parameter table. As shown in FIG. 11, the basestation 1100 mainly comprises a storing unit 1101 and a transmittingunit 1102. Other parts of the base station 1100 not closely related tothe technical solution of the first embedment of the disclosure are notshown in the figure to avoid the ambiguity of the subject matter.

Specially, the storing unit 1101 is configured to store a pre-definedparameter table. As described above, the parameter table may be a CQItable, a differential CQI table or a MCS table. In addition, theparameter table may include the whole entries of a legacy parametertable and some extended entries.

The transmitting unit is configured to transmit to the UE a bitmapindication which indicates a sub-table selected from the pre-definedparameter table.

Specially, the bitmap indication may be transmitted by the eNode B tothe UE via a signaling in the upper layer explicitly or in the physicallayer implicitly. For example, the bitmap indication may be transmitteddirectly via UE-specific RRC signaling semi-statically or implicitlytriggered via bits in DCI format dynamically(specific configurations arevia RRC signaling).

The bitmap indication may be used for indicating the sub-table selectedfrom the parameter table. It should be noted that the number of theentries in the sub-table may be the same as in the legacy parametertable, so that the signaling overhead related to the indication in thephysical layer may be kept unchanged.

The base station 1100 may further comprise a generating unit (notshown). The generating unit is configured to generate the bitmapindication based on wireless link conditions of the user equipment inthe communication system. For example, when the user equipment is at aposition close to cell center, when a carrier for a secondary cell isassigned for the user equipment, or when the user equipment is in auplink transmission, the generating unit generates the bitmap indicationwhich indicates a sub-table including more extended entries. When theuser equipment is at a position far away from cell center, when acarrier for a primary cell is assigned for the user equipment, or whenthe user equipment is in a downlink transmission, the generating unitgenerates the bitmap indication which indicates a sub-table includingmore legacy entries.

Those skilled in the art will understand that the bitmap indication canbe generated by the generating unit based on communication scenariosother than those described above with reference to FIGS. 4-6.

In addition, the base station 1100 may further comprise an informingunit (not shown). The informing unit is configured to inform of the UEan index, such as a MCS index, of an entry based on the sub-table.

Moreover, since the extended parameter table comprises more entries thanthe legacy table, the base station 1100 may further comprise are-indexing unit to re-index the entries.

Specially, for example, for the MCS table, the re-indexing unit mayre-index the selected original MCS entries, so that the index length isstill the same as legacy MCS table. Then, the base station 1100 mayinform one of the new indices to the UE.

In addition, the base station 1100 may further comprise a restoring unitto restore the new indices to the original indices.

Specially, for example, for the CQI table, after receiving the selectednew index from the UE which has been subject to the re-indexing processsimilar to those described above at the UE side, the restoring unit mayrestore the reported new index to the original CQI index based on thebitmap indication.

Next, refer to FIG. 12, which shows schematically the configuration of auser equipment according to the first embodiment of the presentdisclosure. The user equipment 1200 according to the first embodiment isused to configure a parameter table. As shown in FIG. 12, the userequipment 1200 mainly comprises a storing unit 1201 and a receiving unit1202. Similarly, other parts of the user equipment 1200 not closelyrelated to the technical solution of the first embedment of thedisclosure are not shown in the figure to avoid the ambiguity of thesubject matter.

Specially, the storing unit 1201 is configured to store the pre-definedparameter table similar to that described with reference to FIG. 11.

The receiving unit 1202 is configured to receive from the eNode B abitmap indication which indicates a sub-table selected from thepre-defined parameter table.

The user equipment 1200 may further comprise a reporting unit (notshown). The reporting unit is configured to report to the eNode B anindex of an entry based on the sub-table.

In addition, the user equipment 1200 may further comprise a re-indexingunit to re-index the entries in the sub-table, for example, for theextended CQI table, and may further comprise a restoring unit to restorethe received index to the original index, for example, for the extendedMCS table. The configurations and process of the re-indexing unit andthe restoring unit are similar to those in the base station 1100, andare not described here to avoid redundancy.

The communication apparatuses according to the first embodiment of thepresent disclosure have been described above. According to thecommunication apparatuses, higher modulation orders may be supportedflexibly, while the signaling overhead in the physical layer may be keptunchanged, thus achieving a good backward compatibility.

Second Embodiment

FIG. 13 is a flowchart showing an exemplary implementation of thecommunication method according to the second embodiment of the presentdisclosure.

As shown in FIG. 13, the communication method starts at step 1301, wheremultiple parameter tables are defined at both the eNode B and the userequipment.

The parameter may be various communication parameters such as CQI,differential CQI and/or MCS, as described above. Correspondingly, theparameter table may be a CQI table, a differential CQI table and/or aMCS table.

In addition, the parameter table may include at least a legacy parametertable and an aggressive parameter table which includes new modulationorder related entries or new combinations of modulation order and codingrate related entries, which are shown in FIG. 14 schematically. Thelegacy parameter table 1401 as shown in FIG. 14 may be a table definedin standards such as 3GPP TS 36.213, and it may correspond tocommunication scenarios where relatively conservative modulationorders/coding rates are required. The aggressive parameter table 1402 asshown in FIG. 14 may be an extended new table, and it may correspond tocommunication scenarios where relatively aggressive modulationorders/coding rates are required.

Next, at step 702, eNode B transmits to UE an indication which indicatesa parameter table selected from the parameter tables.

Specially, the indication may be a bit indication or a bitmapindication, and it may be transmitted by eNode B to UE via a signalingin an upper layer than the physical layer. For example, the bitmapindication may be transmitted via RRC signaling or bits in DCI format.

It should be noted that the number of entries in any one of the multipleparameter table may be the same as in the legacy parameter table, sothat the signaling overhead related to the indication in the physicallayer may be kept unchanged. Similarly, the indication may be generatedby the eNode B based on the communication scenario of the wirelesscommunication system.

Moreover, the multiple parameter tables may be hard-coded tables, thatis, pre-defined tables in standard and the content is unchangeable. Allpossible tables may be specified in standard, and the eNode B willindicate the UE which table would be used for certain periodsemi-statically via RRC or dynamically via bits in DCI.

It should also be noted that CQI and MCS related tables could havedifferent configurations. There is no need for CQI and MCS to alwaysfollow the same modulation order restriction. Differential CQI tablescould also have different hard-coded versions and eNB indicates whichtables would be used via RRC or bits in DCI format. There is anotherpossibility that RRC signaling is used for configuration/restriction andDCI bits for triggering. For example, multiple hard-coded tables arepre-defined in standards and the RRC signaling is used to indicate whichtables would be used for current configuration, then the specific tablewill be dynamically triggered in each transmission time interval (TTI)via bits in DCI.

With the communication method according to the second embodiment of thepresent disclosure, higher modulation orders may be supported flexibly,and the signaling overhead in the physical layer may be kept unchanged,thus achieving a good backward compatibility.

Hereinafter, the communication apparatus according to the secondembodiment of the present disclosure will be described with reference toFIGS. 15-16. The communication apparatus may be a base station (which isalso referred to as eNode B) or a user equipment (UE), and locates in awireless communication system comprising both the base station and theUE.

First, refer to FIG. 15, which shows schematically the configuration ofa base station according to the second embodiment of the presentdisclosure. The base station 1500 according to the second embodimentmainly comprises a storing unit 1501 and a transmitting unit 1502.

Specially, the storing unit 1501 is configured to store multiplepre-defined parameter tables including at least a legacy parameter tableand an aggressive parameter table which includes new modulation orderrelated entries or new combinations of modulation order and coding raterelated entries as described above. The transmitting unit 1502 isconfigured to transmit to the user equipment an indication whichindicates a pre-defined parameter table selected from the multiplepre-defined parameter tables. The number of the entries in the selectedpre-defined parameter sub-table may be the same as in the legacyparameter table, so that the signaling overhead related to theindication in the physical layer may be kept unchanged.

The other parts of the base station 1500 and the functions thereof aresimilar to those of the base station 1100 according to the firstembodiment of the present disclosure, and will not be described here toavoid redundancy.

Next, refer to FIG. 16, which shows schematically the configuration of auser equipment according to the second embodiment of the presentdisclosure. As shown in FIG. 16, the user equipment 1600 according tothe second embodiment mainly comprises a storing unit 1601 and areceiving unit 1602.

Specially, the storing unit 1601 is configured to store multiplepre-defined parameter tables similar to that described with reference toFIG. 15. The receiving unit 1602 is configured to receive from the eNodeB an indication which indicates a parameter table selected from themultiple pre-defined parameter tables.

The other parts of the user equipment 1600 and the functions thereof aresimilar to those of the user equipment 1200 according to the firstembodiment of the present disclosure, and will not be described here toavoid redundancy.

The communication apparatuses according to the second embodiment of thepresent disclosure have been described above. With the communicationapparatuses according to the second embodiment of the presentdisclosure, higher modulation orders may be supported flexibly, whilethe signaling overhead in the physical layer may be kept unchanged, thusachieving a good backward compatibility.

Third Embodiment

FIG. 17 is a flowchart showing an exemplary implementation of thecommunication method according to the third embodiment of the presentdisclosure.

As shown in FIG. 17, the communication method starts at step 1701, wherea parameter table similar to that in the first embodiment is defined atboth the eNode B and the user equipment.

Next, at step 1702, the eNode B transmits to the UE an indication whichindicates one entry of the parameter table by legacy bits and at leastone unused bit jointly.

That is, the third embodiment according to the present disclosurefocuses on using unused bits combining with current bits, for example,MCS bits in DCI, to indicate the extended parameter table, for example,the extended MCS table.

Specially, there is 5 bits for MCS indication in DCI format currently.Therefore, in order to indicate the extended MCS table and not impact onthe current MCS bits, one option is to combine 1 bit or 2 bit of CarrierIndicator Field (CIF) with MCS bits to jointly indicate extended table(considering the typical scenario of CA is 2 CC in downlink and 1 inuplink so 1 bit is enough for the indication of carrier index and thus 2bits are redundant, which may be used to jointly indicate MCS).

Another option is to combine unused bit in Hybrid Automatic RepeatRequest (HARQ) ID with MCS bits to jointly indicate extended MCS table.How to allocate HARQ ID is pure implementation related issue in eNB. Forexample, only first two bits are used for indication of normal HARQprocess ID so the last 1 bit could be used for other business. In thiscase, the eNB has flexibility to use the last bit in HARQ ID to jointlyindicate MCS.

Except for the above two options, any other solutions to jointly combineunused bits with current 5 bits of MCS to indicate extended table arealso applied. Which redundant bits will be used finally may beconfigured by UE specific RRC in the eNB.

Hereinafter, the communication apparatuses according to the thirdembodiment of the present disclosure will be described.

Similarly, the base station according to the third embodiment mainlycomprises a storing unit and a transmitting unit. Specially, the storingunit is configured to store a pre-defined parameter table including thewhole entries of a legacy parameter table and extended entries asdescribed above. The transmitting unit is configured to transmit to theuser equipment an indication which indicates one entry of thepre-defined parameter table by legacy bits and at least one unused bitjointly, so that the signaling overhead related to the indication in thephysical layer is kept unchanged.

The other parts of the base station and the functions thereof aresimilar to those of the base station 1100 according to the firstembodiment of the present disclosure, and will not be described here toavoid redundancy.

The user equipment according to the third embodiment mainly comprises astoring unit and a receiving unit. Specially, the storing unit isconfigured to store a pre-defined parameter table including the wholeentries of a legacy parameter table and extended entries as describedabove. The receiving unit is configured to receive from the eNode B anindication which indicates one entry of the pre-defined parameter tableby legacy bits and at least one unused bit jointly.

The other parts of the user equipment and the functions thereof aresimilar to those of the user equipment 1200 according to the firstembodiment of the present disclosure, and will not be described here toavoid redundancy.

With the communication method and apparatuses according to the thirdembodiment of the present disclosure, higher modulation orders may besupported flexibly, the signaling overhead in the physical layer may bekept unchanged, thus achieving a good backward compatibility.

Fourth Embodiment

FIG. 18 is a flowchart showing an exemplary implementation of thecommunication method according to the fourth embodiment of the presentdisclosure.

As shown in FIG. 18, the communication method starts at step 1801, wherea parameter table similar to that in the first embodiment is defined atboth the eNode B and the user equipment.

Next, at step 1802, the eNode B transmits to the UE an indication whichindicates one entry of the parameter table by a number of bits, whereinthe number of bits corresponds to the number of entries in the parametertable.

That is, the fourth embodiment according to the present disclosurefocuses on extending the MCS bits directly in DCI format and defining anew transmission mode in standards, such as RAN1 standard. The newtransmission mode may be Mode 9+ as shown in FIG. 19, wherein themodification of DCI format 2C to DCI format 2C+ is intended to extendthe MCS bits from 5 to 6 or even bigger.

Correspondingly, the transmitting unit of the base station according tothe fourth embodiment may be configured to transmit to the userequipment an indication which indicates one entry of the predefinedparameter table by a number of bits, wherein the number of bitscorresponds to the number of entries in the parameter table. Thereceiving unit of the user equipment according to the fourth embodimentmay be configured to receive from the eNode B an indication whichindicates one entry of the predefined parameter table by a number ofbits, wherein the number of bits corresponds to the number of entries inthe parameter table.

The other parts of the base station and the user equipment and thefunctions thereof are similar to those of the base station 1100 and theuser equipment 1200 according to the first embodiment of the presentdisclosure, and will not be described here to avoid redundancy.

With the communication method and apparatuses according to the fourthembodiment of the present disclosure, higher modulation orders can besupported to adapt channel and improve spectral efficiency.

The above embodiments of the present disclosure are only exemplarydescription, and their specific structures and operations do not limitthe scope of the disclosure. Those skilled in the art can recombinedifferent parts and operations of the above respective embodiments toproduce new implementations which equally accord with the concept of thepresent disclosure.

The embodiments of the present disclosure may be implemented byhardware, software and firmware or in a combination thereof, and the wayof implementation does not limit the scope of the present disclosure.

The connection relationships between the respective functional elements(units) in the embodiments of the disclosure do not limit the scope ofthe present disclosure, in which one or multiple functional element(s)or unit(s) may contain or be connected to any other functional elements.

Although several embodiments of the present disclosure has been shownand described in combination with attached drawings above, those skilledin the art should understand that variations and modifications whichstill fall into the scope of claims and their equivalents of the presentdisclosure can be made to these embodiments without departing from theprinciple and spirit of the disclosure.

The invention claimed is:
 1. A communication method performed by a userequipment, the communication method comprising: determining a selectedChannel Quality Indicator (CQI) table, from a legacy CQI parameter tableand an aggressive CQI parameter table, based on a received RadioResource Control (RRC) signaling, the aggressive CQI parameter tableincluding combinations of at least one of higher modulation scheme andhigher coding rate than the legacy CQI parameter table; determining aselected Modulation and Coding Scheme (MCS) table, from a legacy MCSparameter table and an aggressive MCS parameter table, to be used withthe selected CQI table as a set, based at least on the RRC signaling,the aggressive MCS parameter table including combinations of at leastone of higher modulation order and higher Transport Block Size (TBS)index than the legacy MCS parameter table; and controlling communicationbased on one of the combinations of modulation scheme and coding ratecorresponding to a CQI index in the selected CQI table and based on oneof the combinations of modulation order and coding rate corresponding toa MCS index in the selected MCS table; wherein, one of sets of theselected CQI table and the selected MCS table is a first set of theaggressive CQI parameter table and the legacy MCS parameter table or asecond set of the legacy CQI parameter table and the aggressive MCSparameter table.
 2. The communication method of claim 1, wherein: thelegacy MCS parameter table is selected in DCI format 1A transmission. 3.The communication method of claim 1, wherein: a number of bits thatindicate the CQI index in the aggressive CQI parameter table equals anumber of bits that indicate the CQI index in the legacy CQI parametertable, and a number of bits that indicate the MCS index in theaggressive MCS parameter table equals a number of bits that indicate theMCS index in the legacy MCS parameter table.
 4. The communication methodof claim 1, wherein: different carrier components have differentconfigurations of at least one of the selected CQI table and theselected MCS table.
 5. The communication method of claim 1, wherein: thelegacy MCS parameter table and the aggressive MCS parameter table arestored in a memory.
 6. The communication method of claim 1, wherein: thelegacy CQI parameter table and the aggressive CQI parameter table arestored in a memory.
 7. A user equipment comprising: a memory which, inoperation, stores two or more Channel Quality Indicator (CQI) tablesincluding a legacy CQI parameter table and an aggressive CQI parametertable, the aggressive CQI parameter table including combinations of atleast one of higher modulation scheme and higher coding rate than thelegacy CQI parameter table, and two or more Modulation and Coding Scheme(MCS) tables including a legacy MCS parameter table and an aggressiveMCS parameter table, the aggressive MCS parameter table includingcombinations of at least one of higher modulation order and higherTransport Block Size (TBS) index than the legacy MCS parameter table;and a controller which is coupled to the memory and which, in operation,determines a selected CQI table based on Radio Resource Control (RRC)signaling and determines a selected MCS table to be used with theselected CQI table as a set, based at least on the RRC signaling, andcontrols communication based on one of the combinations of modulationscheme and coding rate corresponding to a CQI index in the selected CQItable and based on one of the combinations of modulation order andcoding rate corresponding to a MCS index in the selected MCS table;wherein, one of sets of the selected CQI table and the selected MCStable is a first set of the aggressive CQI parameter table and thelegacy MCS parameter table or a second set of the legacy CQI parametertable and the aggressive MCS parameter table.
 8. The user equipment ofclaim 7, wherein: the controller, in operation, determines the legacyMCS parameter table is the selected MCS table in DCI format 1Atransmission.
 9. The user equipment of claim 7, wherein: a number ofbits that indicate the CQI index in the aggressive CQI parameter tableequals a number of bits that indicate the CQI index in the legacy CQIparameter table, and a number of bits that indicate the MCS index in theaggressive MCS parameter table equals a number of bits that indicate theMCS index in the legacy MCS parameter table.
 10. The user equipment ofclaim 7, wherein: different carrier components have differentconfigurations of at least one of the selected CQI table and theselected MCS table.
 11. The user equipment of claim 7, wherein: thelegacy MCS parameter table and the aggressive MCS parameter table arerespectively stored in a memory.
 12. The user equipment of claim 7,wherein: the legacy CQI parameter table and the aggressive CQI parametertable are respectively stored in a memory.